Recently, a flat panel display (FPD) such as a liquid crystal panel is made larger and therefore requires members in which a large area is precisely microfabricated at the μm order or less. Further, microfabrication of molds and difficult-to-cut materials having a minute shape such as sheet making large roll molds, stop grooves or deep microlenses which are difficult to make with conventional mechanical processing is variously studied.
Further, it is known that, according to ablation processing using an ultrashort pulse laser having the pulse width equal to or less than a pico second (ps) order, it is possible to easily form a minute pattern equal to or less than 1 μm on, for example, a metal surface. Furthermore, various methods have been proposed for a technique which, with this ultrashort pulse laser processing, processes the surface of a target processing material made of a polymer material including resin, semiconductor material, glass material or metal member (see, for example, Patent Literature 1).
Here, when a large area is microfabricated by laser processing disclosed in Patent Literature 1, a target processing material held on a stage needs to be moved and scanned in a wide range in the two-dimensional direction of the X-Y direction. However, the speed of microfabrication in this case is controlled to the speed to movement of the stage, and therefore it is difficult to increase the speed. In addition, to establish synchronization with this slow stage movement, high speed shuttering is applied to a pulse laser beam (hereinafter, also “pulse light”) emitted from a laser oscillator, and a pulse frequency (hereinafter, also “repetition frequency”) is modulated low.
Further, a technique is known in laser processing which microfabricates a predetermined area by two-dimensionally scanning a laser beam in the X-Y direction by means of, for example, a beam scanning unit such as a galvanometer scanner (see, for example, “Patent Literature 2”). However, with the recent technique, two-dimensional scan of pulse light in this case requires positioning precision equal to or more than 10 μm for irradiation spots, and therefore is difficult to apply microfabrication by ablation using pulse laser beams.